1. Field of the Invention
The present invention relates to a computer apparatus, a computer system and an adapter carry-over method in the computer apparatus.
2. Background Art
Blade servers that have plural computers in a single apparatus have been used in recent years to facilitate server management (for example, U.S. Pat. No. 7,058,738). Multi-core design that includes plural processor cores has improved the performance of CPU (Central Processing Unit), and with this improvement, virtual server technologies that allow plural virtual servers to operate in a single computer have been used in order to effectively use CPU. In the virtual server technologies, methods such that physical processors and memory are virtualized by firmware called hypervisor and arbitrary numbers of logical partitions (logical processor) are generated in a computer are used.
A computer uses an I/O adapter such as NIC (Network Interface Card) and FC-HBA (Fiber Channel-Host Bus Adapter) for network communication with other computers and for connection with storage devices. At that time, when plural serves are operated on a single computer as described above, the number of I/O adapters per computer becomes relatively insufficient. As a technology to remedy such a problem, the multi-root PCIe switch technology that allows for connection between plural computers and PCI (Peripheral Component Interconnect) devices or PCI Express (PCIe) devices that are plural I/O adapters has been known.
In the multi-root PCIe switch technology, it is possible to vary the number of PCIe devices that can be connected to a single computer in a scalable manner (for example, U.S. Pat. No. 7,058,738, US Patent Application Publication No. 2006/242353 and others). In the latter disclosing multi-root I/O virtualization technology, the number of PCIe devices can be virtually increased by sharing a single PCIe device. By using these technologies, the shortage of the number of I/O adapters when virtual servers are used can be solved.
Meanwhile, system redundancy has been made to improve availability of systems with a hot standby system that holds operating spare systems in readiness and with a cold standby system that holds non-operating spare systems in readiness. A computer in operation is referred to as an active computer and a computer on standby is referred to as a standby computer or the like.
Because the cold standby system requires longer time to change over systems compared with the hot standby system, and therefore requires longer downtime of the computer system at the time of system changeover. However, the cold standby system does not require expensive cluster software and therefore has been widely used for its advantage in terms of cost.
As an example of switch employing the multi-root I/O virtualization technology, an MR-IOV switch is disclosed in.
“Multi-Root I/O Virtualization and Sharing Specification Revision 1.0, published by PCI-SIG, 2008, 1.2.4.4(p.29)”